it's probably a bug. After you load the preset on the H8000 with sine wave inthe Envelope module, try changing it to Triangle and then back to Sine. It should work. Looks like the module is not correctly updated when the sigfile is compiled.
Regarding the Dynamic String Pad algorithm. It was an attempt to create dynamic selling fx…long ago, when the Dsp4000 was the thing! I don't remember all setails…too many years have passed…but I can say the version with the GATE module works much better to me. I never really liked the way the Envelope module works.
all the best